A super-Earth orbiting the nearby M dwarf GJ 536^⋆

¹ Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain
e-mail: asm@iac.es
² Universidad de La Laguna, Dpto. Astrofísica, 38206 La Laguna, Tenerife, Spain
³ Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain
⁴ Observatoire Astronomique de l’Université de Genève, 1290 Versoix, Switzerland
⁵ Univ. Grenoble Alpes, IPAG, 38000 Grenoble, France
⁶ CNRS, IPAG, 38000 Grenoble, France
⁷ Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal
⁸ Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal

Received: 11 July 2016
Accepted: 5 November 2016

Abstract

We report the discovery of a super-Earth orbiting the star GJ 536 based on the analysis of the radial-velocity time series from the HARPS and HARPS-N spectrographs. GJ 536 b is a planet with a minimum mass Msini of 5.36 ± 0.69 M_⊕; it has an orbital period of 8.7076 ± 0.0025 d at a distance of 0.066610(13) AU, and an orbit that is consistent with circular. The host star is the moderately quiet M1 V star GJ 536, located at 10 pc from the Sun. We find the presence of a second signal at 43 d that we relate to stellar rotation after analysing the time series of Ca II H&K and H_α spectroscopic indicators and photometric data from the ASAS archive. We find no evidence linking the short period signal to any activity proxy. We also tentatively derived a stellar magnetic cycle of less than 3 yr.